Background/Purpose:

Anti-TNF medications are increasingly used in patients with rheumatoid arthritis (RA), and current guidelines recommend holding preoperatively. However, few studies examine actual practice and perioperative safety of TNF inhibitors. This study assesses the preoperative use of anti-TNF medications in RA patients undergoing total knee replacement (TKR), and examines if anti-TNF use increases six month adverse post-operative events or disease flares.

Methods:

This is a retrospective chart review with follow-up. RA patients who had a TKR between June 2007 and May 2010 were identified from a large prospective single institution joint replacement registry. RA cases were identified by ICD-9 code (714.0) or self-report, and then confirmed by chart review. All registry patients receive a six month adverse events questionnaire which is validated by chart review or phone. For this study, patients received a RA focused questionnaire; medications were confirmed by chart review. We examined self-reported RA flare within one month of surgery and six month adverse events, including surgical site infection (SSI), pulmonary embolus (PE), deep venous thrombosis (DVT), pneumonia, any other infection or re-operation. We evaluated patterns of preoperative anti-TNF use, and compared differences in short term adverse events and post-operative flares between those on anti-TNF and non-users using a Chi-squared analysis. Analysis done with SAS version 9.2. This study was IRB approved.

Results:

Of 728 cases reviewed, 194 patients were confirmed as RA (208 cases). Mean age was 61.7 years (SD+/- 11.9), female 86.6%, Caucasian 78.7% and 69.6% had some college education Anti- TNF was used in 86 cases (41.4%): etanercept 59.3%; adalimumab 20.9% infliximab 18.6% and golimumab 1.2%. 86% of the charts documented that anti-TNF should be held and of these, 54 (74%) recommended a specific stop time: mean of 2.4 (SD 2.4) weeks for etanercept (t ?= 35.5 days), 4.6 weeks (SD 6.2) for adalimumab (t ?= 1020 days), and 4.9 (SD 2.15) weeks for infliximab (t ?= 712 days). In anti-TNF vs. non-anti-TNF cases, non-biologic DMARDs or prednisone were used in 67.4% vs. 65.6%. 160 cases (77%) had six month data, and 120 (57.4%) responded to the RA questionnaire. There were 7 confirmed adverse events: 2 PEs, 1 DVT, 2 SSIs, and 2 re-operations. 4 / 7 were in the anti-TNF group (all SSIs and re-operations) and all of these were on etanercept. There was no significant difference between the anti-TNFs and non-anti TNF groups ( p-value=.51). Self-reported RA flare was higher in the anti-TNF groups (22.4% vs. 16.9%), but the difference was not significant (p-value=.47).

Conclusion:

Anti-TNF medication use was not associated with an increased risk of short term adverse postoperative events, though adverse events were rare. Anti-TNFs were held 2 to 4 weeks before TKR, without apparent regard for their pharmacologic half-lives. There appeared to be a non-significant trend towards increased post-operative flares in anti-TNF users. Larger studies should be done to examine if more pharmacologically based timing of anti-TNF withdrawal prior to surgery might minimize the risk of post-operative RA flare while maintaining the excellent safety of these medications.